IMMUNOEXPRESSION PTEN IN ORAL EPITHELIAL DYSPLASIAS AND SQUAMOUS CELL CARCINOMA

Epithelial oral dysplasia (OED) is a risk factor for developing subsequent oral squamous cell carcinomas (OSCC). PTEN is a tumor suppressor gene of the PI3K/AKT pathway, which is 1 of the most deregulated pathways in cancer. Objective: To perform immunohistochemical analysis of PTEN in OED and OSCC samples with different histologic gradations of malignancy. Study Design: Formalin-fixed paraffin-embedded samples of 19 OED and 16 OSCC were included to immunohistochemistry analysis of PTEN (Abcam, clone 31392, 1:400, overnight). Quantitative and qualitative evaluation of PTEN immunostaining in 5 fields at 400 x magnification was performed, correlating PTEN immunoexpression in different degrees of DEO and histologic stages of CEO. Results: The PTEN immunostaining pattern showed both homogeneous and heterogeneous in samples of OSCCs and OEDs. The average number of cells with nuclear immunostaining was significantly higher in OSCCs compared to OEDs and control (P Conclusions: The heterogeneity of PTEN protein expression in OED and OSCC samples was demonstrated. Immunoexpression of PTEN was higher in OSCC and severe and moderate dysplasia compared to the control and mild OED, which suggested the functional inactivation of PTEN in this cancer. This work was supported by grants from Conselho Nacional Desenvolvimento Cientifico e Tecnologico (CNPq).